Citrus greening, also known as huanglongbing (HLB), is a serious disease affecting citrus trees, such as oranges, lemons, and grapefruits. It is caused by a bacterium called Candidatus Liberibacter asiaticus, which is spread by the Asian citrus psyllid, a small insect. Infected trees produce bitter, misshapen fruit and may eventually die. The disease has significant economic impacts on the citrus industry, leading to reduced yields and increased production costs. Efforts to manage citrus greening include controlling the psyllid population, removing infected trees, and developing resistant varieties of citrus plants.